OPTO 22 Optomux B1, Руководство пользователя

Страница: 31 / 33

TROUBLESHOOTING QUESTIONS AND ANSWERS
B1 and B2 User’s Guide
26
Q. I send a command to activate several outputs. The Optomux unit responds with no error, but
none of my outputs come on.
A. If an output does not turn on, check the following:
a.
Make sure you configured the outputs of the Optomux unit correctly. The unit defaults to
all positions configured as inputs on power-up.
b. If power was lost at any time and returned, the unit will have lost its configuration. The unit
will have reported a N00 error to the first command sent after the power-up to indicate
that configuration was lost.
c. If using a digital Optomux unit, make sure you are using output modules with a 5 VDC logic
voltage (OAC5, ODC5, etc.). Sometimes modules with a 15 VDC or 24 VDC logic voltage
(ODC15, OAC24, etc.) are inserted by mistake. The LED may turn on or be dim with the 15
VDC and 24 VDC modules, but there will be no output on the field side.
d.
If the output LED is on, but the load does not turn on, check the field voltage and wiring.
Also, the load may not draw enough current to meet the minimum current requirements
of OAC5 modules (20 mA).
Q. I send a command message to an Optomux unit at address 0, and I get no response. However,
the Optomux’s REC light flashes.
A. The receive lights on all the Optomux boards wired in a multidrop mode should light whenever a
command is sent. Only the unit at the address that matches the command message address should
respond. When an Optomux unit responds, the XMT (transmit) light will flash. At high baud rates,
and for messages with only a short response (“A” only), the flash will be so brief it may be missed
visually.
If the host receives no response, and no flash of the XMT light is visible at the slowest baud rate
(300), then check the following:
a. Make sure the address in the command message matches the Optomux address. Check
the jumpers. A common mistake is a reversal of jumpers. All address jumpers (B0 through
B7) installed are address 0, and all address jumpers (B0 through B7) removed corresponds
to address 255.
b.
Make sure the baud rate is correct between the host and the Optomux unit. All Optomux
units on the same link should be configured to the same baud rate.
c. Make sure you have a solid +5 volts powering the Optomux unit. If the voltage is too low,
the RCV light may flash, but the unit will not be able to respond. Measure the voltage at the
unit’s power terminals — not at the power supply.
d. Check to make sure the communications link is wired with the correct polarity and that the
A group of jumpers is configured correctly.
Q. When I read position 3 of an Optomux analog board, I receive a 0000, which converts to a
decimal -4,096 value when I subtract the 1,000 hex offset.
A. A -4,096 decimal reading may indicate one of the following:
a. You are reading a module position that has no input module installed.
b. You are reading a thermocouple module that has no thermocouple installed, or the
thermocouple probe is open.
c.
An ICTD module has the ICTD wired in reverse.
d.
A 4–20 mA module is wired with reverse polarity.
e.
The field connections are made to the wrong terminals. Field connections vary with each
module. Refer to the module’s data sheet for information on wiring each specific module.
In general, field connections made to the terminals on the rack are made to the terminals