digital panel modules user guide OEM33 3.5 digit LCD digital voltmeter features 3.5 Digit 10mm character height LCD 200mV Full Scale sensitivity Automatic zeroing and polarity indication 11 selectable annunciators Easy to use decimal point selection Built in snap fastener Display hold feature standard O DESCRIPTION ELECTRICAL CHARACTERISTICS T =25 C A CHARACTERISTIC CONDITION MIN TYP MAX UNITS The OEM33 is one of the world s smallest digital Supply voltage (VDD) 9 Volts 7 9 10 V voltmeters. It is an ideal replacement for analogue meters 5 Volts 4.5 5 6 V with advantages of accuracy, size and easy mounting. Supply Current (IDD) 9 Volts 500 900 A The module includes an A/D converter, LCD display of 5 Volts 5 mA 10mm character height, and plastic housing with standard Full scale 199.9 mV dual in line pin terminals for easy insertion into sockets or Input Impedance 100 M PC Board. Reference Voltage 9 Volts 100 mV Overload voltage 20 V Zero I/P Reading 0 +1 Counts DIMENSIONS mm Accuracy 9 Volts +2 +4 Counts at FSD 5 Volts +2 +4 Counts 9 Volts +1 +2 Counts Linearity 5 Volts +1 +2 Counts Resolution 100 V CMRR 70 dB o Temp Coefficient 100 150 ppm/ C Panel cut out 40.5 x 22.5 PIN FUNCTIONS Fastening clips accept panel thickness 0.9 to 3.2mm VDD Positive supply terminal VSS Negative supply terminal for 9 volts operation GD Negative supply terminal for 5 volts operation OPERATING SPECIFICATION IH Input high terminal O Operating temperature 0 to 50 C IL Input low terminal O Storage temperature -20 to 70 C RH Reference high input terminal RL Reference low input terminal Operating relative humidity 80% HOLD1 Connect to VDD for hold and GD for continuous C Analogue Common XBP For driving annunciator DISPLAY HOLD FACILITY BP LCD back plane The OEM33 has a built in digital display hold facility. For D1, D2, D3 Decimal point pins . D1 = .000, D2 = 0.00 D3 = 00.0 normal, continuous operation connect the Hold 1 pin to The decimal point will appear if the corresponding terminal is connected to XBP. the GD pin. To hold the present reading, connect Hold 1 o o to VDD. Do not leave this pin floating or it will drift in and BAT, C, F,~, Annunciators m, , M, K, out of hold mode. V, A, HOLD2 All annunciators not in use must be connected to the BP ORDERING INFORMATION pin for suppression purposes. To light up an annunciator, OEM33 3.5 digit, 200mV LCD Voltmeter connect the corresponding pin to XBP. Revision - 14 27/08/04 USER INSTRUCTIONS CONNECTION DIAGRAM BASIC CONFIGURATION The OEM33 is designed for 5/9V supply. Incorrect supply polarity will destroy the module immediately. It is ready for general use when connected as in fig. 1 for 5V. For 9V supply the module may need calibrating before use as follows. Connect as in fig. 2, apply 100mV to the inputs from a calibrated source and adjust VR1 until the display reads 1000.The input range is 0-199.9mV.Over-range is indicated by displaying a1 in the most significant digit. If the input voltage is reversed, a minus sign is displayed automatically. For 9V operation it is recommended to power from a 9V The module has 3 decimal points. D1, D2, D3 and 11 selectable annnunciators. battery. The inputs are intended to float with respect to the For 5V operation, IL must be connected to GD for supply but if they do not float they must be no closer than non-floating inputs (fig. 1) and to analogue common pin C 1.5V from either VDD or VSS (VDD-1.5V and VSS+1.5V) for floating inputs. In both cases J1 should be closed). see the circuits for non-floating inputs below. APPLICATION CIRCUITS DC VOLTAGE MEASUREMENT DC MULTI-RANGE VOLTAGE MEASUREMENT To measure voltages greater than 200mV For multi-range, use a 2 pole, an attenuator is required. First choose R1. 4 way rotary switch. 1 pole for range select and the other to R1 R2= x VD max. is 199.99mV (Vin/Vd)-1 connect the appropriate decimal point to XBP. EXAMPLES VIN Display VD R1 R2 2V 1.999V 199.9mV 1M 110K 10V 1500rpm 150mV 1M 15K The input impedance becomes R1+R2. Choose accurate stable resistors. Typically, R1=1M. 9M is a practical upper limit. DC MULTI-RANGE CURRENT MEASUREMENT DC CURRENT MEASUREMENT Vs Shunt resistance RS = I IN For multi-range, use, a 2 pole, 5 way rotary switch. 1 pole for It is important to note the power range select and the other to dissipation in the shunt and choose connect the appropriate resistor rating accordingly decimal point to XBP 2 Vs 2 PS= = IIN RS I IN EXAMPLES Current RS PS 200mV 1 0.04W 2A 0.4W 0.1 DC VOLTAGE OFFSET DC VOLTAGE RATIO MEASUREMENT To achieve a zero display reading To determine the ratio between two for a non-zero voltage input, voltages apply the inputs as shown. apply the offset voltage between V2 C and IL. Displayed reading = X 1000 V1 For a positive offset apply a Positive signal to IL w.r.t. C. Apply the input signal between V2 Over range occurs when > 2 IH and C V1 Note jumper J1 must be open Note Jumper J1 must be closed and the track connecting RL to C must be cut NON FLOATING INPUTS (a) NON FLOATING INPUTS (b) Using the formulae choose resistors to Where a single 5V supply is not ensure the analogue inputs are no suitable but you must connect your closer than 1.5V from either VDD or input signal ground to the module VSS (VDD-1.5V or VSS+1.5V) supply ground then either of the two non-floating input circuits can be used. Note that the module is set in 9V supply mode BUT jumper J1 is left open. Revision - 14 27/08/04 anders electronics plc Bayham Place, London NW1 OEU UK Tel: +44 (0)20 7380 8167 Fax: +44 (0)20 7874 1908 www.anders.co.uk