INFICON Maxtek PM-700 Plating Monitor - Manual (Page 69)

PM-700 SERIES PLATING MONITOR
61
The displayed rate, thickness, and efficiency values are absolute. Their negative
sign bits are stored in the probe flag register and are bit mapped as follows:
Table 19 Probe Flag Register
Bit No. Description
5 Negative sign (display thickness)
6 Negative sign (display rate)
7 Negative sign (display efficiency)
The current value is in the units of counts and ranges from 1 to 2999. To convert
this value to the displayed value, multiply by the current scale factor/256
2
and
divide by 10*current decimal point position. This value is an absolute value for
the probe current. Bits 0, 1, 2, and 3 of the Output2 register determine whether
the current is positive or negative or none at all. The bit map for the Output2
register is shown in Table 17 on page 57.
If bits 0 and 1 of the Output2 register are false (=0), then the output current to the
probe-A is zero regardless of the probe current value. But, if bit 0 is true, then the
output current is positive. Or, if bit 1 is true, then the output current is negative.
One important note is that the PM-710 and PM-740 output probe period instead of
the probe frequency. To convert the period to frequency, use the following
equation:
To initiate automatic data logging, the computer would send a one byte message
in the standard format. The variables will be sent in the order they are displayed
in above. For example, to setup the monitor to automatically output the displayed
rate and thickness, the following message would be sent to the monitor:
Header
(2 bytes)
Instruction Code
(1 byte)
Message
Length
(1 byte)
Command
Code or
Message Checksum
(1 byte)
FFh FEh 50h 1h 3h ABh
( )
Period
f
2 6 256 * 500 * 10 * 3 . 98
=