Hydro Instruments 210 Series, Инструкция по эксплуатации

Страница: 31 / 42

Display and Circuit Board
Display is blank
1. Verify the power is turned on to the unit.
2. If it is, check the DC voltage to the analyzer circuit board on terminal connections V- and V+. Refer to
Figure 9.
3. A blank display may indicate a failure of the display, the power supply board or the primary circuit
board. Consult Hydro Instruments or an authorized representative for assistance.
4-20 mA Output channel values are not accurate
1. Verify the output selection is correct. For example, if the output signal on a 5 mg/l analyzer
measuring 2.5 mg/l is something other than 12mA, verify that the output you are measuring is
confi gured to “Resl”.
2. Check the output calibrations at 4mA and 20mA by accessing the appropriate output channel
calibration as detailed in the note on Figure 7.
NOTE: The output calibration numbers from the factory calibration are recorded on the inside of the
electronics enclosure for future reference.
3. Check to see if the Sample Flow Stop alarm is active. If the Sample Flow Stop Alarm is active the
4-20mA outputs will be frozen. Correct the sample water fl ow issue. Once the Sample Flow Stop
alarm has been cleared the 4-20mA outputs will indicate live readings. If the optional sample fl ow
switch is not installed than the setting for the Sample Flow Stop alarm may be wrongfully enabled.
Communication Errors
The MB220 Display board is communicating with the other boards by Modbus over the ribbon cable.
If the ribbon cable is not properly connected to each board, then the MB220 Display board may lose
communication with one or more circuit boards. If so, you would see a “COMM ERROR” message
such as “Node 1 Error”. Node numbers are identifi ed on Figures 10 and 11. As can be seen there,
the MB127 board is Node 1. If such an error occurs, check to ensure that the ribbon cable is properly
connected to all relevant circuit boards per Figure 11.
TABLE 2: Circuit Board Descriptions and Node Numbers
Node Number
(Comm Error)
Circuit Board Board Description Application
1 MB127
Cell Board Measurement Cell
2 MB128
Temp, pH, & Flow Board pH, Temp and 4-20mA input
3 MB114
Four Analog Outputs Board 4-20mA outputs
4 MB104
Four Relay Board Relay outputs
5 MB122
Two In, Two Out Board 4-20mA outputs
6 MB181
Eight Contact Inputs Board Flow Stop Switch
31