Despatch Protocol 3 Controller - Manual (Page 62)

T ROUBLESHOOTING Protocol 3 Controller Owner’s Manual
62 Version 1.2
Copyright © 2013 by Despatch Industries.
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7.
Troubleshooting
7.1. Error Messages and Alarm
Table 20 lists the more common error messages, the possible problems and remedies.
Table 20. Error Messages and Next Steps.
Alarm Status
Possible Problem Next Step
Hi-Limit LED ON 
Problem with thermocouple

Hi-limit setpoint has been
exceeded.
Once the problem has
corrected, press Reset.
DEV HOLD LED
flashing Oven temperature has not entered (or
dropped out of) the Auto Hold band
and the soak timer has stopped Program a slower ramp rate
or if oven is not heating check
heater circuit.
Top PV displays
OPEN Control thermocouple is disconnected
or broken Repair or replace the
thermocouple.
HLPV displays OPEN High Limit thermocouple is
disconnected or broken
Repair or replace the
thermocouple.
7.2. Controller Firmware Revision
Refer to the Protocol 3 Controller Owner’s Manual for instructions on how to enter Product Information.
Protocol Manager Software requires Version 2.3 or later firmware for the Protocol 3 controller. If the
control is version 2.2 or earlier contact Despatch for a replacement.
7.3. Troubleshoot Protocol Manager/Protocol 3 Controller
Communication
For problems communicating between the Protocol Manager and Protocol 3 controller, check each
controller’s communication page for these settings:

Address
o Assign each controller/oven using an RS422/RS485 interface a unique address.
o Default = 1

Baud Rate
o For problems communicating, try a lower baud rate. But start with the default baud rate.
o Default = 19.2K

Parity
o Leave parity at the default setting
o Default = None
In addition to checking for proper settings:

Check cabling between the computer running the software and the oven (Figure 22)

Review schematics for older model serial converters (Figure 23)

Review schematics for newer model serial converters (Figure 24)

Review schematics for USB converter (Figure 25)