Behmor 1600 Coffee Roaster PID Temperature Controller

Simple Addition of a PID Temperature Controller for the Behmor 1600 Coffee Roaster.

Optional switch can disable PID and let roaster work as before, can be useful when preheating roaster for example.

Optional red (PID Power) and green (SSR Power) lamps to indicate the PID is powered and when the SSR has switched on power to the heating element.

Roaster must be switched onto manual "P5" 100% mode, this will power the PID permenantlly during ther roasting cycle and the PID will control roaster temperature via switching the heating element via the SSR.

Once the roaster switches to the cooling cycle, this will automatically cut the power to the PID which will also deernergize the SSR, thus switching the heating element off.

1. Auber Instruments PID Controller Model: SYL-2352
2. Auber Instruments K type Thermocouple, Washer Probe 6 ft with spade connector
3. Auber Instruments 25 Amp AC SSR
4. Auber Instruments External-Mount Heat Sink for 25A SSR
5. Red & Green Compact LED Indicators, 120V AC
6. Hammond Manufacturing 1590DBK Black Aluminum Enclosure 7.4" L × 4.7" W × 2.2" 
7. E-Switch Switch Rocker Dpdt20A 125V
8. 16 Awg High Temperature Silicone Wire
9. 22 Awg High Temperature Silicone Wire
10. 4 × 10-24 Coupling Nut
11. 2 × 3/8" Diameter Bore Rubber Grommet
12. 9 × 10-24×3/8" Round Head Machine Screws
13. 9 × #10 Split Lock Washers
14. 1 × #10-24 Hex Machine Screw Nut
15. 6 × No. 6 Spade Terminal 22 Awg
16. 2 × No. 6 Spade Terminal 16 Awg
17. 7 × 16-14 AWG Automotive Female Quick Disconnect, 1/4"
18. Butt Splice Connector 16 Awg
19. Butt Splice Connector 22 Awg

Recommended Tools:

1. Drill
2. Dremel Rotary Tool
3. Terminal Crimping Tool
4. Step Drill Bit
5. 3/16" Drill Bit
6. 1/4" Drill Bit
7. Dremel EZ Metal Cutting 1½" Disc
8. Screw Driver
9. Pliers and/or wrench
10. File
11. Carpet Tape
12. PPE Safety Glasses
13. PPE Mask

• Print and cut front panel template.
• Use carpet tape to mount template on enclosure narrower sidewall.
• Drill out corners of switch and PID cutouts with 1/4" drill bit.
• Drill two holes for green and red indicator lamps with 1/4" drill bit.
• Use Dremel with cutting disc to cut out the PID and switch cutouts.
• Use file to finish cutouts for PID and switch.

• Print and cut lid template.
• Use carpet tape to mount template on enclosure lid.
• Drill out corners of SSR cutout with 1/4" drill bit.
• Drill 4 holes for Heat Sink screws using 3/16" drill bit.
• Use Dremel with cutting disc to cut out the SSR cutout.
• Use the file to finish cutout for SSR.
• Apply heat conductive grease from the syringe to the SSR mounting surface spread as an even film across the entire surface.
• Mount SSR on the heat sink using the two supplied screws.
• Mount SSR and heat sink onto the enclosure lid using the remaining 4 screws.

• Remove Behmor right-hand panel cover by removing 6 Phillips screws:
• 1 Philips screw on the rear 45° sloping side
• 2 more Philips screws on the rear
• 3 more Philips screws on the underside.
• Once all screws are removed slide the cover towards the front and then carefully away from the rest of the roaster.
• It will be attached with a small red and black cable to the roaster main circuit board. This powers the cooling fan.
• The wire can be detached via the connector from the main circuit board, there's a small clip on the underside of the connector that needs to be pushed up in order to unplug the connector. See the arrow in the first picture.
• Align enclosure onto the right panel, so that top of the enclosure aligns with the highest vent and the PID front panel when inserted in the enclosure lines up with the front of the roaster (flush with the front of cover panel).
• Then mark 4 holes to mount the enclosure onto the panel as well as a 1/2" hole in the centre of both for the rubber grommets. Make sure holes aren't located where the panel vents are situated.
• Drill out mounting holes on both enclosure and panel cover with 3/16" drill bit and use the step drill bit to drill out 1/2" hole for rubber grommets.
• Install rubber grommets in enclosure and panel cover.
• Then secure enclosure to panel cover using eight 10-24 × 3/8" screws and split washers and four 10-24 coupling nuts.

• Remove Behmor left-hand panel cover by removing 7 Phillips screws:
• 1 smaller Philips screw between door and the panel cover half way up.
• 1 Philips screw on the rear 45° sloping side
• 2 more Philips screws on the rear
• 3 more Philips screws on the underside.
• The target location of the thermocouple is to mirror the location of the thermistor temperature sensor which is between the two small screws on the right side of the roaster's interior (see red arrow in the photo above).
• Drill a 3/16" hole on the left side of the roaster wall in order to mirror that location. Install thermocouple with 10-24 screw, nut and split washer.
• Thread the cable through the cavity in the top from the left opening of the roaster to the right opening and out from behind the roaster's control panel. As the cable is too long, it can be looped once in that cavity to store the length of the cable. About 1' will need to protrude from the right side of the roaster.
• Re-install left panel cover.

For this step, reference the attached document "Behmor PCB Wire Color Code.pdf".

1. We need only 3 wires from the roaster to the PID enclosure:
2. Live lead: unplug the blue wire from terminal #15 on the circuit board, crimp a 1/4" female quick disconnect wire terminal on a 16 AWG high-temperature wire and install in place of the blue wire on terminal #15. Use red wire for this to help distinguish from the wire in step #2.
3. Heating Element Wire: cut off the 1/4" female quick disconnect wire terminal from the blue wire that was disconnected in step #1 and use 16 AWG butt splice to splice a 16 AWG black high-temperature wire.
4. Common Lead: As the common lead will only power the LED lights, PID and SSR it only needs to be 22 AWG. The common lead can be spliced onto either wires from terminals #17 or 18. Another alternative is to take photos of all the connectors and terminals on the circuit board (so as to know how to reassemble later) disconnect the mall, remove the circuit board and solder a 22 AWG common lead onto the copper lead of the common bus (that connects terminals 17 and 18). Then reinstall the circuit board and all the connectors and terminals.
5. Thread these 3 wires and the thermocouple shielded wire through the rubber grommets into the enclosure.
6. Reattach the fan cable to terminal #6
7. Reinstall the right panel and enclosure onto the roaster.

Reference the schematic for this step.

Also DPDT Switch technical drawing and SYL-2352 PID User Manual.

Some important notes before wiring up the. components:

1. Note the wire thicknesses noted in the schematic.
2. Make sure LED lamp wires are threaded into through the enclosure lamp holes, then through lamp retaining nuts before connecting them.
3. Make sure to thread PID wires through it's rectangular retaining clip then out through the enclosure cutout, before connecting wires to the PID. Make sure the rectangular retaining clip is oriented the right way.
4. Also switch wires should be fed out through the switch enclosure cutout.

Follow the schematic to wire all the components:

1. The red live 16 AWG wire should be connected to one of the common poles of the DPDT switch terminal #1. Use a 1/4" female quick disconnect wire terminal.
2. The black heating element 16 AWG wire should be connected to the other common pole of the DPDT switch terminal #2. Use a 1/4" female quick disconnect wire terminal
3. Bridge terminals #2b and #1b with 16 AWG wire using 1/4" female quick disconnect wire terminals.
4. Using a 1/4" female quick disconnect wire terminal, attach terminal #1a of the switch to SSR load terminal #1, PID power terminal #9 (both using spade terminals) and the green lamp. Note wire gauges for each in the schematic.
5. Using a 1/4" female quick disconnect wire terminal, attach terminal #2a of the switch to SSR load terminal #2, using spade terminal and the red lamp. Note wire gauges for each in the schematic.
6. Attach common wire to the two lamps and PID power terminal #10 using spade terminal.
7. Attach SSR positive control terminal #3 to PID positive control terminal 7 using spade terminals.
8. Attach SSR negative control terminal #4 to PID negative control terminal 8 using spade terminals.
9. Attach thermocouple yellow (positive) lead to PID terminal #4.
10. Attach thermocouple red (negative) lead to PID terminal #5.
11. Install switch into the enclosure, it should snap into place.
12. Bend all the PID terminals 90°, then install PID into the enclosure, use the rectangular retaining clip to fasten it into the front panel.
13. Tuck all the wires carefully so they don't get pinched on the enclosure or any of the interior components, and secure the lid with the SSR and heat sink onto the enclosure using the 6 provided screws.

Follow the attached PID user manual.

1. In order to power up PID, the roaster must be powered up in manual mode P5. Press the 1 Lbs button, then Start, followed by P5 (P5 light will start blinking).
2. Make sure also that the PID bypass switch isn't in bypass mode. The green light should be illuminated.
3. Press the PID "SET" button for 2 seconds to enter the parameter setup menu.
4. While in the parameter setup mode, use, ▲and▼ buttons to modify a digit. Use A/M button to select the digit that needs to be modified. To exit the parameter setup mode. press the A/M and SET key at the same time. The controller will automatically exit if no key is pressed for 10 seconds. Note the changed parameter will be automatically registered without pressing the SET key. Pressing the SET key will advance to the next parameter.

Below are the parameters that should be changed or unchanged:

• ALM1 - Unchanged
• ALM2 - Unchanged
• Hy-1 - Unchanged
• Hy-2 - Unchanged
• Hy - Unchanged
• At - Unchanged
• I - 1700
• P - 40
• d - 45
• t - 2
• Sn = 0
• dP - Unchanged
• P-SL - Unchanged
• P-SH - Unchanged
• Pb - Unchanged (See comment (1) below)
• OP-A - Unchanged
• OUTL - Unchanged
• OUTH - Unchanged
• AL-P - Unchanged
• COOL - Unchanged
• Addr - Unchanged
• bAud - Unchanged
• FILt - Unchanged
• A-M - 1 (This enables manual mode, see comment (2) below).
• LocK - Unchanged
• EP1-EP8 - Unchanged

Comments

(1) As the PID thermocouple is located in a different location from the roaster thermistor sensor, there might be a difference between the two measured temperatures. This can be solved using the Pb (Input Offset) parameter.

During roasting, compare PID measured temperature to the roaster measured chamber wall temperature (by holding button "B" on the roaster).

The difference can be set in parameter Pb so that the two measurements are the same.

For example, if the PID measured temperature is 300° but the roaster measured chamber wall reads 290°, set parameter Pb to -10. This should make both temperatures the same.

(2) If parameter A-M is changed to 1, this enables manual mode. This can be useful for example after 1ˢᵗ crack to "coast" to roast, see this video for more info. To enter manual mode press the A/M key, the A-M LED will light up. Then press the SET button to switch to display mode 2 (where output power is displayed on the bottom row). The output power can be set manually, for example, 50 means 50% (equivalent to roaster manual mode P3).

To return to automatic mode, press A/M again (A-M LED will switch off).