Vaisala HMP228 - Manual (Page 41)

HMP228
M210282en-A Operating Manual
35
• If the settings need to be changed, press CL:
−
the quantity (aw, T) starts flashing; it can be changed with the
arrow keys and acknowledged with the ENT key
−
the lower limit starts flashing
−
acknowledge the lower limit with ENT or start changing it by
pressing CL; a new lower limit is given with the arrow keys
−
the upper limit starts flashing
−
acknowledge the upper limit with ENT or start changing it by
pressing CL; a new upper limit is given with the arrow keys
• When channel 1 has been set, the programme goes on to channel 2;
the procedure is the same as with channel 1.
4.8 Checking and calibrating the analogue outputs
The operation of analoque outputs can be tested by forcing the outputs to
given values. See on appendix n. ITEST command.
4.8.1 Measurement of output currents using test points
If a current output has been connected e.g. to a process computer, the output
current cannot be measured at the output connector X2 without disconnecting
the external load. The output current can, however, be measured at test points
CH1+/CH1- and CH2+/CH2- without disconnecting the output wires. These
test points can therefore be used in one point offset correction against an accu-
rate reference or in checking the current output without disconnecting the
analogue output from the process.