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Appendix C - Analog Input Conversions

Response_D = {(k - 4096) / 4095 } * (F - Z) + Z

Where:
	ResponseD is actual value in the same engnieering units as F and Z. k is the 4 digit hex response from the I/O PLEXER converted to decimal. F is the full scale value of the module and Z is the zero scale of the module. These are shown for the standard modules in the table below.

duTec Module	F	Z	Units
IV50M	50	0	mVolts
IV100M	100	0	mVolts
IV1	1	0	Volts
IV5	5	0	Volts
IV10	10	0	Volts
IV5B	5	-5	Volts
IV10B	10	-10	Volts
II420	20	4	mAmps

Example:		k = 19FCH = 6652D II420 Module
Response ValueD:		= [({6652 - 4096} / 4095) * (20 - 4) + 4]
		= [(2556 / 4095) * 16 + 4]
		= [(0.624) * 16 + 4]
		= 9.984 + 4
		= 13.984 mA

If the first hex digit is F, then the value represents a negative offset. Use the formula that applies.

	Positive Offset
OffsetD = [(k / 4095) * (F - Z)] + Z
	Negative Offset (First digit is F)
OffsetD = {[(k - 65536) / 4095] * (F - Z)]} + Z

Where:
	Offset is the actual offset in decimal as seen by the I/O PLEXER. k is the 4 digit hex value converted to decimal that was returned by the I/O PLEXER. The formula to use is chosen based on the first digit of this number. F is the full scale value of the module and Z is the zero scale of the module. These are shown for the standard modules in the table below.

duTec Module	F	Z	Units
IV50M	50	0	mVolts
IV100M	100	0	mVolts
IV1	1	0	Volts
IV5	5	0	Volts
IV10	10	0	Volts
IV5B	5	-5	Volts
IV10B	10	-10	Volts
II420	20	4	mAmps

Example:	k = 01FFH = 511D IV5B Module
OffsetD	= [(511 / 4095) * (5 - {5 -})] + {-5}
	= [0.125 * 10] - 5
	= 1.25 - 5
	= -3.75 Volt (NOTE: This is a -5 to 5 Volt Module!!)
Example	k = FC00H = 64512D IV10 Module
OffsetD	= {[(64512 - 65536) / 4095] * [10 - 0]} + 0
	= {[-1024 / 4095] * 10} + 0
	= { -0.25 * 10} + 0
	= -2.5 Volt

Negative offset calculations are taken care of by subtracting the value from 65,536. Please use the appropriate formula.

	Positive Offset
k = [(Desired - Z) / (F - Z)] * 4095
	Negative Offset
k = 65536 + {[(Desired -Z) / (F - Z)] * 4095}

Where:
	k is the decimal number that is converted to 4-digit hex value and plugged into the instruction. Desired is the actual offset you want in the same engineering units as F and Z. F is the full scale value of the module and Z is the zero scale of the module. These are shown for the standard modules in the table below.

duTec Module	F	Z	Units
IV50M	50	0	mVolts
IV100M	100	0	mVolts
IV1	1	0	Volts
IV5	5	0	Volts
IV10	10	0	Volts
IV5B	5	-5	Volts
IV10B	10	-10	Volts
II420	20	4	mAmps

Example:		Desired = 0.02 Volts IV1 Module
		k = [(0.02 - 0) / (1 - 0)] * 4095
		k = [0.02 / 1 ] * 4095
		k = 0.02 * 4095
		k =  81.9D = 0051H
Example:		Desired = -11 Volts IV10B Module
	k = 65536 + {[(-11 - [-10]) / (10 = [-10])] * 4095}
	k = 65536 + {[(-11 +10) / 20] * 4095}
	k = 65536 + {[-1 / 20] * 4095}
	k = 65536 + { -0.05 * 4095}
	k = 65536 - 204.75
	k = 65331D = FF33H

	GainD = k / 4096
Where:
	Gain is the decimal value of the Gain set by the I/O PLEXER. k is the 4-digit hex k data field converted to decimal.
Example:
	k returned is 1800H = 6144D
		GainD = 6144 / 4096
			= 1.5

k = (Desired * 4096) Convert to 4 hex digits

Where:
	k is the four hex digit data entered in the instruction. Desired is the actual decimal value required.
Example:
	Desired = 1.1 k = 1.1 * 4096 k - 4505.6D = 1199H

These two fields set the upper and lower range limits. Any time an analog input goes above or below these limits a latch is set. These values are set using a 3-digit hex value. The 1000_H offset is not used on these values.

l or m = {[(Range_D - Z) / (F - Z)] * 4095} Convert to 3 Hex Digits

Where:
	l or m is value that needs to be converted to 3 hex digits and entered into the instruction. RangeD is the actual range value that is desired in the same engineering units as F and Z. F is the full scale value of the module and Z is the zero scale of the module. These are shown for the standard modules in the table below.

duTec Module	F	Z	Units
IV50M	50	0	mVolts
IV100M	100	0	mVolts
IV1	1	0	Volts
IV5	5	0	Volts
IV10	10	0	Volts
IV5B	5	-5	Volts
IV10B	10	-10	Volts
II420	20	4	mAmps

Example:	IV5B Module Upper Limit = 4 Volts Lower Limit = -4 Volts
Upper Limit:	l = {[(4 - [-5]) / (5 - [-5])] * 4095}
	l = {[(4 + 5) / (5 + 5])] * 4095}
	l = {[9 / 10] * 4095}
	l = 3685.5 = E65H
Lower Limit:	m = {[(-4 - [-5]) / (5 - [-5])] * 4095}
	m = {[(-4 + 5]) / (5 + 5)] * 4095}
	m = {[1 / 10] * 4095}
	m = 409.5 = 199H

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